Machine learning engineer Jobs in Carlsbad, CA

Please note that we are unable to provide visa sponsorship for this position.

About Proper Voltage

Proper Voltage is unlocking the next generation of battery technology across robotics, data centers, and defense.

We're building intelligent battery systems that make advanced chemistries (sodium-ion, lithium-titanate, lithium-silicon) work in products that were never designed for them. Humanoid robots can upgrade power systems without redesigning their entire platform. Data centers get safer, cheaper backup power. Drones and autonomous vehicles get higher energy density without lengthy integration cycles.

If you want to work on hard engineering problems that matter this is the place.

Test Engineer

Full-Time · On-Site

THE ROLE

We know what we're building. Getting it from design through validation and into production is where it gets hard, and that's where you come in.

You'll write test plans, not just run them. Build fixtures when nothing off-the-shelf fits. Come back from the data with conclusions, not just charts. The work spans early characterization all the way through production validation. You need to be comfortable at both ends and useful in the middle.

We're not looking for someone who needs the problem fully defined before they start. You'll have a team of test engineers and technicians alongside you, and the engineering calls are yours to make.

If you've spent real time in a lab and a machine shop, read on.

WHAT YOU’LL ACTUALLY BE DOING

Most days involve some mix of the following but not always in a predictable order:

– Designing and running cell and systems test programs: capacity, rate capability, aging, DCIR, abuse, thermal, EMC

– Building the hardware to make it happen: fixtures, enclosures, busbars, cooling setups, custom one-offs

– Turning data into conclusions, not just charts

– Pushing back on test requests that don't make sense and proposing something better

– Setting the standard on execution, builds, and lab practice

– Writing it down: test plans, procedures, results . Make it clean enough that someone else can pick it up

– Keeping the lab running: calibration, safety, general good citizenship

HOW WE WORK

We're a startup, which means everyone wears more hats than their job title suggests and the best ideas win regardless of who has them. We want someone who takes ownership of their work, speaks up early when something's off, and helps raise the standard for everyone around them. Not because they're told to, but because that's how they operate.

You'll have full access to the team, real context on why the work matters, and people around you who are invested in getting it right. We move fast and we move together.

QUALIFICATIONS

Required

– B.S. or higher in Mechanical Engineering, Electrical Engineering, Materials Science, or equivalent

– 3+ years of hands-on battery testing experience (cells, modules, or packs)

– Demonstrated fabrication ability. Show us something you’ve built

– Comfortable with Python, MATLAB, AI, or equivalent tools for data analysis

– Experience writing and owning test plans from concept through final report

Preferred

– Direct battery system and cell characterization and testing

– CAD proficiency (SolidWorks, Fusion 360)

– Familiarity with UL 9540, IEC 62133, UN 38.3, or similar standards

– Experience in an early-stage or R&D environment

Who You Are

– You don't wait to be told exactly how to do something - you figure it out and check in when it matters

– You're comfortable saying "I haven't done this before, but here's how I'd approach it"

– You leave things better than you found them. A cleaner bench, better-labeled cables, improved fixture

– You take safety seriously, especially around energized cells and high-current systems

Working Conditions

– Full-time, on-site lab environment

The pay range for this role is:
100,000 - 130,000 USD per year(Carlsbad Office)

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